[Ifeffit] Energy shift

[Matt Newville]

HI Eugenio,

I'm not sure I understand the question.  Do you mean that you ran
Feff8 calculations on these Er materials and see energy shifts between
the calculations?   Or do you mean that you see an energy shift
between the calculations and experimental spectra?

If it's the former -- I'm not sure.  I'd expect that the calculated
edges for these would be pretty similar.  I don't have a lot of
experience with Feff8 and hydroxide structures (I probably should!),
but I might suspect that having H in the calculation could cause an
small energy shift. Perhaps someone here with more experience can
comment on that.

If it's the latter (calculations vs experiment),  ~5 eV seems
reasonable.  Feff's calculation of E_f is not perfect, and I wouldn't
be too surprised by an absolute energy shift of a few eV for a
rare-earth L edge.   In addition, setting the absolute energy in an
experiment can easily be off by a few eV at 8 to 9 keV.  Since you say
you ran a Ni foil, I'd expect the experimental calibration to be
better than that, but it might depend on details of the beamline.

--Matt

On Mon, Jan 26, 2009 at 9:06 PM, Eugenio Otal <eugenioh at gmail.com> wrote:
> Hi all,
> I finished simulations of Er(OH)3, ErO(OH) and Er2O3, when I compared the
> spectras with the samples and I found a shift in energy equal to 5.5 eV.Even
> between the meassured and calculated spectra of Er2O3, which was previously
> calibrated with a niquel film standard.
> Is this shift part of the bussines?
> Thanks, euG
>
>
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